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新型无变压器的串联混合有源电力滤波器拓扑

电力电子 2005年第2期3卷 55-58页

作者： n.raghavan T.Ellinger J.Petzoldt V.Krishna K.S.Swarup

本文提出了一种新型无变压器的串联混合有源电力滤波器(TL-SHAPF)的拓扑。有源滤波器和电容是串联关系,然后和电感并联,这样一种总体的结构不通过变压器而是直接串联到线路上。在该拓扑结构中,在串联谐振和并联谐振概念基础上采用了电... 详细信息

本文提出了一种新型无变压器的串联混合有源电力滤波器(TL-SHAPF)的拓扑。有源滤波器和电容是串联关系,然后和电感并联,这样一种总体的结构不通过变压器而是直接串联到线路上。在该拓扑结构中,在串联谐振和并联谐振概念基础上采用了电流分离的疗法。源电流被提供了两个通路:一个是谐波电流通路,另一个是基波电流通路。在固定参考坐标系中得到了从低通到带通变换的控制方法。控制器对系统性能的影响用状态空间法来描述。文章也给出了所建模型及仿真结果。

关键词：新型无变压器串联电力滤波器拓扑混合有源电力滤波器串联谐振拓扑结构变压器并联谐振谐波电流

Correlation of microstructure and magnetic properties in Sm(Co_(bal)Fe_(0.1)Cu_(0.1)Zr_(0.033))_(6.93) magnets solution-treated at different temperatures

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Rare Metals 2019年第1期38卷 20-28页

作者： Cheng Xu Hui Wang Tian-Li Zhang Alexander Popov raghavan Gopalan Cheng-Bao Jiang School of Materials Science and Engineering Beihang University M.n. Miheev Institute of Metal Physics Ural Branch of Russian Academy of Sciences International Advanced Research Centre for Powder Metallurgy and new Materials(ARCI) IITM Research Park

The correlation of microstructure and magnetic properties in Sm(Co_(bal)Fe_(0.1)Cu_(0.1)Zr_(0.033))_(6.93) magnets solution-treated at different temperatures was systematically investigated. It is found that the magnets solution-treated at 1219℃ possess a single 1:7 H phase, exhibiting the homogeneous cellular structure during further aging treatment, leading to the optimum magnetic properties. However, for the magnets solution-treated at 1211 and 1223℃,2:17 H or 1:5 H secondary phase will also form besides 1:7 H main phase, which cannot transform into cellular structure,thus deteriorating the magnetic properties greatly. The irreversible magnetization investigations with recoil loops also propose a non-uniform pinning in the magnets induced by the secondary precipitates. At proper solution temperature, Zr is supposed to occupy the Fe-Fe dumbbell sites in the form of Zr-vacancy pairs, leading to the minimum c/a ratio and thus stabilizing the 1:7 H phase. Finally,Sm(Co_(bal)Fe_(0.1)Cu_(0.1)Zr_(0.033))_(6.93) magnets with the maximum energy product and intrinsic coercivity at 550℃ up to 60.73 kJ·m^(-3) and 553.88 kA·m^(-1) were prepared by powder metallurgy method.

关键词： Sm2Co17 Solution treatment Phase constitution Demagnetization curve squareness

Modelling of microwave assisted hot-air drying and microstructural study of oilseeds

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International Journal of Agricultural and Biological Engineering 2016年第6期9卷 167-177页

作者： Mohamed Hemis Ruplal Choudhary nathalie Becerra-Mora Punit Kohli Vijaya raghavan University Djillali Bounaama Khemis Miliana Road of Theniat ElhadKhemis MilianaAin Defla 44225Algeria Department of Plant Soil and Agricultural SystemsSouthern Illinois UniversityCarbondaleIL 62901USA Department of Chemistry and Biochemistry Southern Illinois UniversityCarbondaleIL 62901USA Bioresource Engineering McGill UniversitySte.Anne de BellevueQC H9X 3V9Canada

A modelling study was performed to solve the heat and mass transfer problems between grain and the ambient air encountered during drying by microwave assisted hot-air dryer,under low microwave(MW)density of 0.2 W/***(Brassica napus),soybean(Glycine max)and corn(Zea mays)seeds were chosen due to their inherent high oil *** electron microscopy(SEM)was used to study the effect of drying conditions on the structural characteristics of these oilseeds.A mathematical model was adapted to simulate drying of one seed of canola,soybean and *** process of water transfer was modelled based on the effect of vapour pressure on the water molecules inside the *** was observed that when the difference between the vapour pressure inside the grain and the surrounding air was higher than,the drying rate increased which led to cracks in the *** showed that the drying rate decreased when the temperature of air inside the cavity of the microwave increased for all the oilseeds studied,because of the reduced differential vapour pressure between the grain and the ambient *** the other hand,the drying rate increased if the temperature of the inlet air was reduced because the difference between the two pressures *** was concluded that by controlling the ambient air,the grains could be protected against popping and cracking because of lower vapour pressure differential during MW assisted hot-air drying.

关键词： mathematical modelling oilseeds MW assisted drying drying rate SEM images

Environmental Infrasound and Its Impact on Public Health in the Kashmir Region

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Open Journal of Earthquake Research 2019年第3期8卷 165-190页

作者： raghavan Gopalaswami Shakil Ahmad Romshoo Rakesh Chandra Thennaarassan natarajan Retired Advanced Systems and Technology Analyst Formerly with DPSU Government of India Hyderabad India Department of Earth Sciences University of Kashmir Srinagar Jammu & Kashmir State India Geologist Junior Research Fellow Department of Earth Sciences University of Kashmir Srinagar Jammu & Kashmir State India

In earlier published studies it was shown that an anomalous degree of human physiological ailments and a psychology of sustained anger and violence exist in highly populated countries located on boundaries of colliding Tectonic Plates in three continents at Latitude 34° north. The Valley of Kashmir in northern India is also located exactly on this latitude, hence chosen for detailed experimental verification of this phenomenon. This region also suffers from chronic public health hazards. Infrasound is very low frequency acoustic wave with frequencies ranging from 0.01 Hz to 20 Hz. It emanates from earthquakes, geological Faults, colliding tectonic plates and atmospheric wind turbulence. Hearing protections like ear muffs and ear plugs offer little protection. One single earthquake can cause multiple infrasound sources in a region. It is shown how regional geomorphology in the Kashmir Valley enhances and sustains this phenomenon. Both the percentage of population with hearing disabilities;and casualties due to social violence increase or decrease in proportion to frequency of earthquakes. Infrasound is shown to be the causal linkage. Public health hazards due to environmental infrasound closely resemble public health hazards actually being suffered by the population in Kashmir as established by formal and extensive medical investigations. Hence a Field Study was carried out to locate and record infrasound emissions in ten locations near 34°n latitude in Kashmir Valley. An analytical technique was developed to integrate infrasound spectrum in specific locations with public health hazards. It was discovered that infrasound recorded in South Kashmir around 34°n latitude at the locations of highest amplitude lies in proximity of Active Faults from earthquake ruptures;and in proximity to a large field of past earthquakes that took place in 2006-2012. A comprehensive public health security system needs to be set up very urgently. Technological measures are iden

关键词： Environmental Infrasound Public Health Hazards Social Violence Regional Field Study Active and Passive Sound Cancellation

ZnCl2 Catalyzed Synthesis of Various Parabens under Microwave Irradiation

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ZnCl2 Catalyzed Synthesis of Various Parabens under Microwav...

第十二届全国微波能应用学术会议

作者： G．S．Vijaya raghavan Department of Bioresource Engineering McGill University 21111 Lakeshore RoadSte-Anne-de-BellevueQCH9X 3V9Canada

The synthesis of various parabens using ZnCl2 as catalyst under microwave irradiation was studied. More than 97% of conversion can be achieved on the synthesis of n-butyl paraben within 2 minutes under microwaves. During the synthesis of ethyl and n-butyl paraben, a transition curve was observed on the temperature profile. During this period, temperature increases slower than normal. On the synthesis of sec-butyl paraben, ZnCl2 showed great advantage ,over concentrated H2SO4 as catalyst. When ZnCl2 was applied on the reaction of p-hydroxylbenoic acid with 1-octanol, no paraben was obtained, but the existence of di-n-octyl ether and 2-octene were detected.

关键词： n-butyleparaben Microwave-assisted synthesis ZnCl2 transition state athermal octylether

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离子选择电极阵列测定土壤中硝态氮

中国无机分析化学 2022年第1期12卷 91-96页

作者：苏睿苑锋吴俊锋位文涛 VIJAYA raghavan 胡建东河南农业大学机电工程学院河南省农业激光技术国际联合实验室郑州450002 McGill大学生物资源工程系加拿大蒙特利尔H9X3V9 小麦玉米作物学国家重点实验室郑州450002

土壤硝态氮反映土壤短期氮素供应水平,实时了解土壤硝态氮的含量为精准农业和农业面源污染防控提供支撑,因此,在线实时检测土壤硝态氮方法突破就显得十分迫切。土壤硝态氮中的硝酸根离子在土壤中的高水溶性和流动性为全固态硝酸根离子... 详细信息

土壤硝态氮反映土壤短期氮素供应水平,实时了解土壤硝态氮的含量为精准农业和农业面源污染防控提供支撑,因此,在线实时检测土壤硝态氮方法突破就显得十分迫切。土壤硝态氮中的硝酸根离子在土壤中的高水溶性和流动性为全固态硝酸根离子选择电极高敏感检测土壤中硝态氮提供了条件,固态硝态氮离子选择电极的离子选择膜反应硝酸根离子在被测溶液中的浓度。采用全固态硝酸根离子选择电极ELIT nO_(3)^(-),且与温度电极和pH电极融合组成电极阵列对土壤饱和溶液中的硝酸根离子进行检测。设计了高输入阻抗运算放大电路对电极信号进行采集,并通过微处理控制蠕动泵完成土壤硝态氮待测溶液连续流动测定及实时传输结果。实验结果表明,电极响应时间≤15 s,斜率-51.63 mV/decade,线性范围10^(-5)~10^(-2.2) mol/L,最低检测限10^(-5.23) mol/L。相对标准差在0.78%~4.5%,加标回收率均在90.0%~110%。与紫外可见分光光度法测试结果相比,相关系数(R^(2))为0.9952,为土壤硝态氮在现场检测奠定技术基础。

关键词：面源污染硝态氮(nO_(3)^(-)-n) 电极阵列固态离子选择电极(ISE)

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扰动扩散流动分析法测定土壤氮、磷技术研究

农业环境科学学报 2022年第8期41卷 1846-1854页

作者：李灿李振峰马刘正张伟李晓冬 VIJAYA raghavan 胡建东河南省农业激光技术国际联合实验室河南农业大学机电工程学院郑州450002 河南问道光电科技有限公司郑州450002 McGill大学生物资源工程系加拿大蒙特利尔H9X3V9 小麦玉米作物学国家重点实验室郑州450002

随着国家对农业面源氮、磷污染防治力度的加大,土壤氮、磷测定技术迫切需要改善。本研究在对常规的扩散对流(Dispersion convection)和强迫对流(Forced convection)流动分析方法基础上,提出了扰动扩散(Perturbation diffusion)流动分析... 详细信息

随着国家对农业面源氮、磷污染防治力度的加大,土壤氮、磷测定技术迫切需要改善。本研究在对常规的扩散对流(Dispersion convection)和强迫对流(Forced convection)流动分析方法基础上,提出了扰动扩散(Perturbation diffusion)流动分析方法,以实现土壤氮、磷全自动化快速测定与分析。扰动扩散流动分析方法是将样品和试剂定量化后集中在化学反应腔中进行反应,然后程序控制蠕动泵对化学反应腔中反应物进行反复扰动,待化学反应完全稳定后流入光电探测单元完成土壤氮、磷含量测定。采用取自湖北潜江的土壤样品对扰动扩散流动分析方法进行了系统验证,实验结果表明,本研究提出的方法与常规紫外可见分光光度法对氮、磷测定相比,基于硫酸钠和碳酸氢钠联合浸提的土壤铵态氮测量值相关系数为0.9155,基于氯化钙浸提的土壤铵态氮、硝态氮和水溶性磷测量值相关系数分别为0.9985、0.9901和0.9911。铵态氮、硝态氮和水溶性磷的检出限分别为0.0554、0.0203 mg·L^(-1)和0.0084 mg·L^(-1),相对标准偏差(RSD,n=7)分别为1.8%、4.8%和1.0%。

关键词：土壤速效氮土壤速效磷扰动扩散化学反应腔吸光光谱可调光程

Synthesis and Biological Evaluation of novel Homopiperazine Derivatives as Anticancer Agents

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Journal of Cancer Therapy 2011年第4期2卷 507-514页

作者： Simin Teimoori Kuppusamy Panjamurthy Kambappa Vinaya Doddakunche S. Prasanna Sathees C. raghavan Kanchugarakoppal S. Rangappa 不详

In search of new anticancer agents, a series of novel 1-benzhydryl-4-(substituted phenylcarboxamide / carbothioamide)-1,4-diazepane derivatives were designed, synthesized and characterized using 1H nMR, LCMS and elemental analysis. These molecules were evaluated for their anti-cancer activity by trypan blue exclusion and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on B-cell leukemic cell line, Reh. Carboxamide moiety containing derivatives showed good activity compared to the corresponding carbothioamide derivatives. In particular, 4-benzhydryl-n-(3-chlorophenyl)-1,4-diazepane-1-carboxamide showed good activity with IC50 value of 18 μM.

关键词： Cancer Therapy Cytotoxicity 1 4-Diazepane Isocyanates Isothiocyanates